Various systems for optical data transmission from a space station (satellite) travelling on low earth orbit to optical ground terminals are known and deployed. The primary function of these systems is to reliably transmit data from a data source to a optical ground terminal.
Non-geostationary satellites on low earth orbit have line-of sight communication contact with the optical ground terminal for a limited amount of time during each satellite pass. Therefore the achieved speed of downlink channel is of upmost importance, since a great amount of data has to be transmitted to the optical ground terminal in a short amount of time for which a satellite pass lasts.
Furthermore, since the line-of sight communication contact is broken after a short amount of time of a satellite pass and can be established again only at the next satellite pass after a further revolution (or not even), the reliability of the transmission is essential.
An other aspect that has to be taken in consideration in the design of a low earth orbit to earth communication system is the budget as far as the electrical power consumption is concerned. Therefore the less effort is required to obtain the same transfer rate performance the better.